I have suffered with acne since the age of 11 and the only thing that cleared it for me was going on the pill, dianette. Unfortunately this caused it's own set of problems as I was kept on it for much longer than I should've been due to incompetent doctors...
I have tried the antibiotics oxytetracycline, minocycline and doxycycline. None of these did anything for me even when combined with a topical zinc oxide (zinert) antibiotic too.
Over the counter benzoyl peroxide gels and creams such as quinoderm or pan oxyl can offer short term effects but often make the skin very dry and sore and bleach clothes or anything else they come into contact with.
All the options have their strengths and weaknesses. How old is your dd?
My best friend suffered in her teenage years so took a 12 month course of roaccutane, she has never since had a single spot-now 25.
I would try the minocycline for a max of 6 months, if it is going to help at all it should show signs within about 3.
Products wise I can recommend neutrogena oil free wash (it's in a pump bottle, orange gel-boots).
If the acne is very persistent then dermologica do an acne range of products, these are not cheap though and can be harsh so may only be able to use them every other day. It is best to go to a dermalogica store for a free consultation if you are able to.
I hope something works for her, it can be truly miserable